Every time they find a bone chip or a broken tooth, they’re ready to call it yet another “extinct human species.” On the basis of evidence you could hold in the palm of your hand and still have room for bubble gum, we have the whole “Denisovan” cottage industry.
Someday somebody’s going to find a rusty old pop-top tab and National Geographic’s going to run an article on “our mysterious beer-brewing human relative.”
The latest are space aliens that have been here. And there is always the shadow people and the shape-changers.